This invention relates to peristaltic pumps which utilize flexible tubing. More particularly this invention relates to an improved mounting system for the surface against which flexible tubing is compressed in a peristaltic pump.
The operability of peristaltic pumps depends on the successive and repetitive compression of a length of flexible tubing which causes the fluid within the length of flexible tubing to flow. Accuracy of fluid flow from a peristaltic pump can only be maintained if the amount of compression of the flexible tubing can be duplicated each time a new piece of flexible tubing is operatively engaged with a peristaltic pump head.
Problems have arisen in maintaining accurate fluid flow rates in peristaltic pumps because of the varying sizes and durometers of flexible tubing employed. The problem of maintaining accurate fluid flow rates is compounded with increasing viscosities of the fluid to be pumped. In addition if the flexible tubing is not properly positioned with respect to the pump rotor and the surface against which it is compressed or if the pump head has a slight eccentricity, the rotating pump head may bind against the flexible tubing thus causing the rotation of the pump head to cease. Various attempts to overcome these problems have been made by adjustably mounting those portions of a peristaltic pump which repetitively and successively compress the flexible tubing. This adjustable mounting is designed to provide self correction for eccentricities in the pump head itself or irregularities in the flexible tubing. While improving performance these adjustable mounting systems have made peristaltic pump heads difficult to clean and difficult to manipulate when placing the flexible tubing in contact with the pump rotor.
These problems of the prior art have been overcome by the present invention which encompasses a floating compression surface for use with a peristaltic pump. The floating compression surface is biased into position with respect to the pump rotor and against the flexible tubing so that it applies a constant force on the flexible tubing as the pump rotor turns. As those portions of the pump rotor repetitively and successively compress the flexible tubing the surface against which the flexible tubing is compressed will rotate on a pivot mount. This rotation will allow the compression surface to respond to any irregularities in the pump rotor or in the flexible tubing. In this manner flexible tubing of varying sizes and durometers may be used with a single pump head without affecting pump accuracy.